Polyvore is a great site where you can create collages from images all over the web. It's mainly a fashion site but there are images of housewares, enviroments, photoshoots...pretty much anything. And if you can't find what you're looking for there you can download the Polyvore "clipper" which allows you to clip photos from almost anywhere online (with a few exceptions). The nice thing is that when you see something you like you can save it to your "closet" and then give it tags to make it easy to locate things later. I've been using it just for fun since last spring but I used it to find clothes for an assignment I had last semester and I'm now using it for this one.
If you make an account please be sure to add me! I could use some real life Polyvore friends.
Here's my latest set for visual interest...
